In satellite communication and other communication scenarios, the signal strength of uplink transmission is restricted by transmit power of a user equipment, and the transmission performance can not be ensured in the case of a high path loss. Taking a Voice-over-IP service as an example, a data packet including 224 bits is generated every 20 ms, where these 224 bits need to be transmitted in 20 ms. If the 224 bits are transmitted in a Transmission Time Interval (TTI), then there is such a high encoding rate so that the received signal-to-noise ratio of a base station is lower than the demodulation threshold of the data packet, thus the base station can not perform correct demodulation.
There are two existing solutions:
Firstly, the data packet is transmitted repeatedly in time domain, e.g., transmitted repeatedly for 20 times, thus the user equipment transmits the same data packet at a higher total amount of power, and the base station can demodulate correctly the data packet by integrating the data received for 20 times.
A problem of this solution lies in the low spectrum efficiency due to that a Physical Resource Block (PRB) occupied by the user equipment all the time can not be reused by another user equipment.
Secondly, the 224 bits are divided into 20 small data packets which are transmitted in 20 sub-frames. Thus the encoding rate in each sub-frame is lowered accordingly, so the base station can demodulate correctly each small data packet in each sub-frame to thereby resume the original data packet.
A problem of this solution lies in that each of the small data packets into which the data packet is divided will come with an additional overhead, e.g., a Media Access Control (MAC) header overhead, a Cyclic Redundancy Check (CRC) check bit overhead, etc., thus greatly increasing the total overhead and lowering the transmission efficiency.
In summary the spectrum efficiency and the transmission efficiency of uplink transmission may be low at the restricted power of uplink transmission.